From the following numbered list of characteristics, decide which pertain to (a) precipitation hardening, and which are displayed by (b) dispersion strengthening.

(1) The strengthening mechanism involves the hindering of dislocation motion by precipitates/particles.

(2) The hardening/strengthening effect is not retained at elevated temperatures for this process

(3) The hardening/strengthening effect is retained at elevated temperatures for this process

(4) The strength is developed by a heat treatment

(5) The strength is developed without a heat treatment

(a) 1,3,5 (b) - 1,2,4

(a) 3,5 (b) 1,2,4

(a) 1,2,4 (b) 3,5

(a) 1,2,4 (b) - 1,3,5

(a) - 1,3,4 (b). 1,2,5

(a) 1,2,4 (b) - 1,3,5

Explanation:

(a) precipitation hardening is also known as particle hardening or particle hardening, it is a heat treatment technology used to increase the yield strength of fine materials including aluminum, magnesium, nickel, titanium and highly structured alloys of steels and stainless steels.

so correct choice are

(1) The strengthening mechanism involves the hindering of dislocation motion by precipitates/particles. (2) The hardening/strengthening effect is not retained at elevated temperatures for this process. (4) The strength is developed by a heat treatment.

and

(b) dispersion strengthening is spread hardened. Because of the dispersion hardening, the metal contains small, rigid particles, which limits the speed of displacement and thereby increases the strength properties.

so correct choice are

(1) The strengthening mechanism involves the hindering of dislocation motion by precipitates/particles. (3) The hardening/strengthening effect is retained at elevated temperatures for this process. (5) The strength is developed without a heat treatment.